Proton exchange membrane (PEM) water electrolysis is a significant technology for large-scale green hydrogen production. While Platinum on Carbon (Pt/C) is state-of-the-art cathode catalyst due to its moderate hydrogen binding energy and high resistance to acid corrosion, its high Pt loadings significantly increases costs.
Schematic illustration for confinement of single-site Pt by the enriched asymmetric p electrons with boosted activity and stability for acidic HER (Image by XU Mingxia)
In a study published in Joule, a research team led by Prof. DENG Dehui and Prof. YU Liang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaborations with Prof. LU Junling from the University of Science and Technology of China (USTC) and Prof. YU Hongmei from the DICP, developed a highly efficient and stable catalyst for acidic hydrogen evolution. This catalyst employs enriched asymmetric π electrons on the surface of a chainmail structure to create a unique confinement effect, enhancing both the activity and stability of surface-confined platinum (Pt) atoms.
The researchers designed a chainmail catalyst consisting of a cobalt-nickel (CoNi) nano-alloy encapsulated in monolayer graphene. They discovered that electron transfer from CoNi to the carbon layer, along with 3d-2p electronic interaction, led to an enrichment of asymmetric π electronic states on the graphene surface. After depositing Pt single atoms using atomic layer deposition, these enriched asymmetric π electrons exhibited a unique confinement effect on the Pt atoms.
This confinement operates through two synergistic mechanisms: First, electron transfer from CoNi to Pt via the graphene layer results in electron-rich Pt site, optimizing hydrogen adsorption energy and promoting hydrogen desorption, thereby improving catalytic activity. Second, strong interactions between the asymmetric π electrons and the Pt 5d orbital enhance the structural stability of Pt sites, boosting the durability of the catalyst.
Furthermore, the researchers assembled a proton exchange membrane (PEM) water electrolyzer with this catalyst. It achieved an ultra-high current density of 4.0 A cm−2 at 2.02 V and maintained excellent durability over 1,000 hours at 2 A cm−2, using only 1.2 μgPt cm−2 Pt loading. Moreover, they assembled a 2.85 kW PEM water electrolyzer using this catalyst operated stably for over 300 hours at an industrial current density of 1.5 A cm−2, highlighting its outstanding industrial application potential.
“This work provides a new idea for deveolping high performance, long-life and low-cost catalysts for hydrogen production via acid water electrolysis,” said Prof. DENG.
Key words: Chainmail catalyst; Acid hydrogen evolution; Asymmetric π electron; Electronic confinement; Single-site Pt.
Link:
https://dicp.cas.cn/xwdt/ttxw/202506/t20250610_7801421.html
https://doi.org/10.1016/j.joule.2025.101968
